1. Field of the Invention
Methods and apparatuses consistent with exemplary embodiments relate to driving an alternating-current (AC) motor, and more particularly, to driving an AC motor while periodically obtaining a rotator angle of the AC motor.
2. Description of the Related Art
In a method of driving an AC motor, dS- and qS-axes target current values in a synchronous reference frame are used.
Thus, based on a current rotator angle, dS- and qS-axes driving current values in a stationary reference frame are transformed to dS- and qS-axes driving current values in the synchronous reference frame to be fed back. In addition, based on a current rotator angle, dS- and qS-axes control voltage values in the synchronous reference frame are transformed to dS- and qS-axes control voltage values in the stationary reference frame to perform a control.
Accordingly, it is important to accurately determine a current rotator angle, and to do this, a resolver is used in a related art. For example, referring to Korean Patent No. 0176469, a technique of measuring a location of a rotator by attaching a resolver to a servo motor is disclosed. Here, the resolver generates location data of the rotator.
Thus, according to a related art method and apparatus for driving an AC motor as described above, using an additional rotator location detecting apparatus such as a resolver causes a large size of an apparatus for driving the AC motor and high manufacturing costs.
For example, a resolver, signal connection connectors and cables, and a device (e.g., a resolver-to-digital converter (RDC)) and a circuit for an output signal of the resolver must be added.